1. Field of the Invention
The present invention relates to 4-alkenyl-2-azetidinone derivatives, a process for preparing 4-alkenyl-2-azetidinone derivatives and multicyclic compounds prepared using 4-alkenyl-2-azetidinone derivatives. More specifically, the present invention relates to a 4-alkenyl-2-azetidinone derivative having a novel structure represented by the following chemical formula 1, in which an alkenyl group such as 1,3-dien-2-yl or 1,2,4,5-hexatetraen-3-Yl is substituted at the C-4 position of azetidinone; to a process for preparing the 4-alkenyl-2-azetidinone derivative by reacting 4-acetoxy-2-azetidinone with organic indium, which is prepared by reacting a propargyl halide derivative with indium; and to a novel multicyclic compound prepared using the compound represented by the following chemical formula 1 as an intermediate in the Diels-Alder reaction.

wherein, Q is CH or C═CH; R1: is a hydrogen atom, a hydroxyalkyl group or a protected hydroxyalkyl group having 1 to 6 carbon atoms; and R2 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group; provided that, a compound, in which Q is CH, R1 is a protected hydroxyalkyl group and R2 is a hydrogen atom, is excluded.
2. Description of the Related Art
β-lactam is a cyclic amide compound that forms a base skeleton for compounds known as antibiotics such as penicillins and cephalosporins, and it is generally called as “2-azetidinone”. Ever since 2-azetidinone derivatives were discovered by L. A. Fleming in 1928, many studies have been conducted. Moreover, 2-azetidinone derivatives are the most frequently used antibiotics as a material for injection and oral administration in the present.
2-Azetidinone derivatives are used widely as β-lactam antibiotics, thus, it is very important to introduce a functional group selectively to a specific position of the compound.
Inherent structural and chemical characteristics of β-lactam have been a matter of concern for organic synthesis researchers in the past. Therefore, many synthetic methods and various β-lactam antibiotic derivatives have been developed. Further, studies on introducing various substituents to β-lactam are being actively conducted at this moment (Synth. Commun, 1997, 27, 3083; Tetrahedron 1987, 43, 2467; Synlett 1999, 4, 447; J. Chem. Soc., Perkin Trans. 1, 1999, 1695; Tetrahedron Lett. 1987, 28, 5103; J. Chem. Soc., Perkin Trans. 1, 1999, 1695; J. Org. Chem. 2001, 15, 5208; J. Org. Chem. 2001, 15, 5208; J. Org. Chem. 2002, 67, 1925; Encyclopedia of Inorganic Chemistry. Vol 3 (CED. R. B. T. Kingl), 1994, p. 1513).
However, the 2-azetidinone represented by the chemical formula 1, in which a 1,3-dien-2-yl or 1,2,4,5-hexatetraen-3-yl group is introduced to the C-4 position of β-lactam, is a novel compound that has not been reported in any literature at this point. And, its process for preparation has also not been reported. Furthermore, a process for synthesizing a multicyclic compound by using the compound in the Diels-Alder reaction has not been reported in any literature.